EFFECT OF 4D TRANSITION-METAL ATOM RH DOPING ON THERMOELECTRIC-POWER,MAGNETIC-SUSCEPTIBILITY, THERMAL-EXPANSION AND X-RAY PHOTOEMISSION SPECTRA IN THE CHARGE-TRANSFER TYPE NONMETALLIC STATE OF NIS

We report the following two remarks of the Rh impurity effect on the c harge-transfer (CT) type nonmetallic state (below the nonmetal-metal t ransition temperature: T-t) of 3d transition metal compound NiS. (1) A lthough the nearest neighbouring M-M (Ni or Rh) and S-S distances incr ease with increasing x, dT(t)/dx<0. The Rh substitution gives a broad peak with the Fermi edge. A positive sign of T-linear contribution of the thermoelectric power turns to negative one at the critical concent ration (x(c)) in Ni1-xRhxS. Below T-t, a Curie constant is observed an d increases with increasing x. It is suggested that an impurity band i ntroduced by the Rh atoms leads a change of the electronic state of Ni atoms and the suppression of the CT gap. (2) An empirical relation (d T(t)/d\C-N\>0) is found on Ni1-xRhxS, Ni1-deltaS and NiS1-y Se-y, wher e C-N is the phonon-drag coefficient. The slope dT(t)/d\C-N\ becomes s maller in Ni(1-x)M(x)S with the early 3d transition metal impurities ( M: Ti, V and Cr).